PRESSURE GRADIENT AND LIQUID HOLDUP IN IRRIGATED PACKED TOWERS

An examination of the influence of liquid holdup on effective pore size suggests that, for a fixed gas flow, pressure gradient below the loading point should be proportional to (1 - kHt)-5 where Ht is the total holdup and k an empirical coefficient approximately equal to 2/(a × effective pore size), a being the packing external area per unit packed volume. Experimental results with air flow through (-inch Raschig rings having dry voidage 0.70 are satisfactorily correlated with k = 2.1. When total holdup is calculated as the sum of experimental static holdup and operating holdup calculated by the author's recently proposed method, the value k = 2.0 is found. An initial part of the holdup has no effect on the pressure gradient. The final equation for these rings is: where Δp is the pressure gradient, UG the superficial gas velocity, d the nominal ring size, gas density, and μG gas viscosity. The influence of varying dry voidage is not considered. © 1969, American Chemical Society. All rights reserved.